Gold alloy.



sra'rns arana orricii.

KARL GUSTAV PAUL RICHTER, 0F PFORZI-IEIM, GERMANY, ASSIGNOR TO THE FIRM OF DR. RICHTER & 00., 0F PFORZHEIM, GERMANY.

GOLD ALLOY.

1,1e5,4.as.

No Drawing.

To all whom it may concern:

Be it known that I, KARL GUs'rAv PAUL Ric'H'rER, chemist and doctor of philosophy, a citizen of the German Empire, and resident of Pforzheim, in the Grand Duchy of Baden, Germany, with the post-office address 23 Zerrennerstrasse, have invented new and useful Improvements in Gold Alloys, of which the following is a specification.

Gold alloys of a white color are known, for instance gold aluminium, gold iron, gold-nickel. goldpalladium, gold-platinum. gold-tin. These alloys, which all consist of only two metals, have, however, certain disadvantages which hinder their technical application. As to the binary (and certain ternary) alloys of gold with platinum and palladium, these are much too costly for practical use; for such white gold alloys must be sold at such a price as is equivalent to that of an ordinary goldalloy of equal content of gold. The alloys with aluminium, tin, nickel and the like, present, indeed, no particular difliculty in respect to their cost, but they are so hard and brittle that they cannot be worked.

According to the present invention, alloys which fulfil in every respect the requirements of practice, can be made by substituting more or less for metal of the palladium group (palladium, iridium, osmium,

ruthenium, rhodium) a metal of the iron nickel group, particularly nickel. In this manner alloys are obtained, the manufacture of which is not substantially dearer than that of the ordinary gold alloys, while on the other hand the brittleness produced by addition of nickel alone is removed completely by the combination of nickel with the noble metal, the said alloy being malleable and adapted to be formed into articles of jewelry. Obviously, instead of pure gold. copper-gold alloys may be used as the starting material. In this case, however, the content of copper must not exceed -a certain Specification of Letters Patent. Patented De 28, 1915. Application filed April 30, 1913. Serial No. 764,482.

limit, because an excess is attended by a passage of -the desired white color into a reddish tint. By a correct choice of the proportions it is possible to obtain alloys which consist of gold copper and nickel alone without any other noble metal, and yet exhibit substantially the desired properties.

The composition of the alloy may vary within wide limits. Investigation has shown, however, that the most advantageous composition for the alloy to be added to the gold is as follows: Palladium .5 to 20 atoms per cent. A metal or metals of the nickel group-70 to 94: atoms per cent. Copper 4 to 30 atoms per cent. This addition is considered as a whole, that is to say if, for example, the alloy consists of as per cent. gold and 100-0? per cent. of the addition, the latter has the composition given above in per cent.

A suitable composition of alloy made in accordance with my invention may be, for example, as follows: gold 57 atoms per cent., nickel 7.5 atoms per cent., palladium 35 atoms per cent.

By atomsper cent. I mean percentages based on the atomic weights of the quanti- KARL GUSTAV PAUL RICHTER.

Witnesses:

JOSEPH PFEIFFER, J on. HELLER. 

